Infants born to mothers who use cocaine during pregnancy have greater morbidity. Preliminary observations suggest the presence of multiple cardiovascular abnormalities such as greater left ventricular mass, persistent hypertension, greater prevalence of ST segment elevations (suggesting transmural ischemia) and higher vagal tone. These abnormalities were observed in asymptomatic cocaine exposed newborns during the first 2 days of life. To determine the cardiovascular effects of in-utero cocaine exposure on newborns, the proposed study has following aims: Aim l - To detect the cardiovascular abnormalities in the newborn period; Aim 2 - To study the natural history of these abnormalities during the first 2 months of life. A cohort of asymptomatic infants (n=420) will be studied in the newborn nursery. Cocaine exposure or nonexposure will be determined by the positive maternal urine screening and clinical interview and will be substantiated by toxicology studies of infants urine or meconium. The study subjects will be divided into three groups. Group l includes newborn infants exposed to cocaine during pregnancy; because of the widespread concurrent use of alcohol, cigarette and marijuana smoking among these mothers, these infants will be included under Group l. To delineate the cardiovascular effects of cocaine, their data will be compared with two other groups: Group II will include newborn infants with in utero exposure to alcohol, cigarette and/or marijuana smoking. Subjects exposed to other drugs, including cocaine, will be excluded from this group. Group III includes control newborn infants who are not exposed to any drugs during fetal life. At birth and at 2 months of age, all infants will be evaluated by two- dimensional and Doppler echocardiograms, 3 channel Holter monitors for ST segment elevations and spectral analysis of heart period, and blood pressure measurements. The inter-relationship of these abnormalities and their effect on infant morbidity will then be determined. Persistence of these abnormalities may provide an insight into the long term morbidity of these patients. Therefore, it is crucial to understand the natural history of the cardiovascular abnormalities before measures can be directed toward their treatment and prevention.